The invention relates to a dental implant with single- or multiple roots, shaped according to the tooth socket or dental root with protruding macro retentions for immediate and delayed tooth replacement.
The established methods of placing dental implants is drilling an implant hole into the bone, inserting the implant into the prepared cavity by tapping and/or screwing. Prefabricated rotation-symmetric implants of varying forms, lengths and diameters require several weeks healing period.
The method with preformed rotationally symmetric implants does not work in cases where primary stability cannot be achieved due to incongruence of the tooth socket and the rotation-symmetric implant. In such cases first a bone healing period is necessary, since the incongruence of the tooth socket to the pre-fabricated rotation-symmetric implant does not allow for primary stability. Therefore it is an advantage to design the dental implant according and congruent to the individual extraction socket.
Prior German Pat. No. DE 101 09 118 A disclosed an individually tailored tooth implant based on an exact impression of the extracted tooth, enlarged about twice the distance of the periodontal ligament, provided with grooves and finally fixed into the bone with press-fit.
Prior WO Pat. No. 88/03391 disclosed a slightly enlarged root analogue press fit technology implant with undercut cavities, distributed equally over the entire root surface.
Another possible technique described in U.S. Pat. No. 5,603,616 A und U.S. Pat. No. 5,427,526 A is a preformed, custom-manufactured, conical, rotation-symmetric, slightly enlarged single root press-fit technology implant reflecting a major portion of the root. The retention elements are uniformly distributed around the implant surface to provide a screw like mechanism when the implant is rotated in the alveolar bone.
Prior German Pat. No. DE 41 00636 A describes a root shaped implant produced by copy milling without any details on the design of the implant surface.
German Pat. No. DE 195 13 881 describes a method enlarging the implant by doubling the width of the periodontal ligament. The whole bone contact section has a number of rectangular, equidistantly spaced, honeycomb-shaped cavities.
U.S. Pat. No. 4,187,608 concerns an exact replica of the extracted tooth, manufactured from porous metal or ceramic through a special sinter process for better adherence and ingrowths of bone matrix.
US Pat. No. US 2005/0048440 A describes an identical replica with special treatments e.g. etching, sandblast, hydroxyapatite coverage and/or drill holes of the implant surface for improved bone adherence.
None of the above mentioned patents using root replicas were clinically sufficiently successful and for that reason all these methods are not established for routine clinical use. Due to the failures of these kinds of dental implants till now rotation-symmetric implants are the state of technique, when immediate tooth replacement with a dental implant is provided.